Turn the key to S mode [one past pgm clockwise[its not marked on ther lock]]
hold down the cheque key and power up.
Next, in order, press the top left button followed by bottom left button, followed by top right button and finally bottom right button [cash]
Allocate the memory as required [ATTENTION TO NUMBER OF PRICE LEVELS AT THIS POINT] MEMORY ALLOCATION CANNOT BE CHANGED AFTER YOU HAVE ACCEPTED THE CHOICES AT RAM CLEAR!
All that then remains is to reprogram your till from scratch.
If you have the luxury of time, I would suggest not spending too long programming until the machine has been plugged in for 24hrs then test the batteries by unplugging it for as long as possible [up to a week should test the batteries] if it says void mode after this test, the on board battery will need to be replaced [i have never yet had an incident on a 5200 that required battery replacement, but there's a first time foir everything]